Major findings to date involve progress in elucidating the neuropathology of schizophrenia. New results support the hypothesis that decreased numbers of glutamate pyramidal cells (or decreased reuptake activity in the cells) in the medical temporal lobe of schizophrenics with abnormal connections to the dorsolateral prefrontal cortex (DLPFC). We have assayed pyramidal cells with mRNA probes for the glutamate transporter. Synapse formation has been measured with mRNA probes for synaptophysin and GAP-43. mRNA probes related to brain development such as brain derived neurotrophic factor (BDNF) and limbic system associated membrane protein (LAMP) have also been used. The following table summarizes the results of six studies of two cohorts of schizophrenics and controls using two assays for four mRNA's in two brain regions. Results: Plus signs (+) indicate significant change for schizophrenia RNase protection in situ** Region mRNA assay* hybridization _____________________________________________________________________ hippocampus** gultamate transporter + + synaptophysin normal + GAP-43 normal + BDNF + DLPFC GAP-43 + *_Schizophrenics (n=19); depressed suicides (n=15); normals (n=19) **_Schizophrenics (n=9) and normals (n=7) ***_also entorhinal cortex (ERC) with in situ hybridization studies